A tag is a keyword or label that categorizes your question with other, similar questions. Using the right tags makes it easier for others to find and answer your question.
For challenges related to the processing and placement of whitespace characters (mainly, but not limited to spaces, tabs and line feeds), like challenges related to indentation. For challenges about t…
For challenges pertaining to problems in the field of Physics.
This challenge involves the manipulation of complex numbers, including parsing and printing them as well as performing complex arithmetic. This tag also encompasses generalised complex numbers like qu…
For challenges involving recursive functions, or functions or programs calling itself, directly or indirectly.
For questions that relate to probability or measurements, either outputting or parsing.
Used for challenges where answers make reference to themselves or their characteristics, such as length or character values. Since this is a subset of the [quine] tag, many of the same restrictions ap…
describes challenges related to factoring numbers and polynomials. Not related to the Factor programming language.
Tasks involving using Stack Exchange API.
A challenge either involving using logic-gates as the coding language or outputting logic gates.
Obfuscation refers to making code (or other information) more difficult to understand
for challenges related to hexadecimal, or base 16, a number system that often uses the digits 0 ‐ 9 and a ‐ f. Only use this tag on challenges specific to base 16, rather than generic [bas…
Code bowling is a competition to solve a particular problem in the most bytes possible. Must be used with other restrictions so that arbitrarily high scores aren't trivially possible.
In a Rosetta Stone challenge, the goal is to write a solution using as many programming languages as possible.
For challenges where trigonometry plays an important role.
Challenge involving processing colors. It can be either for graphical output or manipulation on color codes.
For challenges about rearranging a set of mathematical operators or numbers to fulfill a certain expression.
for challenges involving integration or differentiation of functions.
For challenges which are specific to numbers represented in floating-point format.
for challenges which require answers to still work when a random edit to the source code is made.
For challenges relating in some way to encoding messages using classical (pen and paper) ciphers. For modern ciphers, such as AES, use the [encryption] tag instead.
For challenges related to creating or implementing an algorithm.
For challenges pertaining to mathematical logic and boolean algebra.
This challenge is related to the C++ language. Note that challenges that require the answers to be in a specific language are generally discouraged.
Word Puzzles are "problems" presented to users, consisting of spelling/vocabulary challenges. The "problem" is solved when the user(s) decipher the correct spelling.
A high-level data structure, made of nodes, each with a maximum of 2 children (left and right). Nodes with no children are called leaves, and two nodes with the same parent are known as siblings.
indicates that the challenge involves Roman numerals
This challenge is related to assembly languages. Note that challenges that require the answers to be in a specific language are generally discouraged.
for challenges involving the factorial of a number, the product of the numbers from 1 to n
This challenge is directly related to solving, creating, or otherwise working with sudoku puzzles.
For challenges that ask for a function or involve functions in some way. (Also known as methods or subroutines.)
For challenges concerning the Rubik's Cube or variations like the Pocket Cube.
Challenges involving searching through some data to find a certain element or elements.
for challenges involving the game of tic-tac-toe (https://en.wikipedia.org/wiki/Tic-tac-toe).
Challenges that involve summarizing a large amount of data in a single, much smaller number.
For challenges involving either three-dimensional graphics, three-dimensional geometry or spatial data structures in three dimensions (e.g. octrees).
Used for challenges that consist of multiple sub-challenges ("holes"), somehow combining the scores into one score. (Note: combining multiple unrelated challenges together is off-topic)